Method for manufacturing three-dimensional shaped object and three-dimensional shaping device

ABSTRACT

A method for manufacturing a three-dimensional shaped object includes: a first shaping step of forming a first layer in contact with a stage provided with a recessed portion by changing a relative position between a discharge unit and the stage while discharging a molten material from the discharge unit toward the stage; and a second shaping step of stacking one or more layers on the first layer by changing the relative position between the discharge unit and the stage while discharging the molten material from the discharge unit toward the first layer. The stage has a first region including a region on the recessed portion and a second region different from the first region, and in the first shaping step, the first layer is formed by making a first supply amount which is a supply amount of the molten material supplied from the discharge unit to the first region per unit area larger than a second supply amount which is a supply amount of the molten material supplied from the discharge unit to the second region per unit area.

The present application is based on, and claims priority from, JP Application Serial Number 2019-099865, filed May 29, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a method for manufacturing a three-dimensional shaped object and a three-dimensional shaping device.

2. Related Art

For example, JP-A-2018-183930 describes a technique of shaping a three-dimensional shaped object by stacking a molten material on a stage having fine pores in order to reduce warpage of the three-dimensional shaped object.

In the above technique, a part of the molten material stacked on the stage enters the fine pores and is cured, so that the three-dimensional shaped object is less likely to peel off from the stage, and the warpage of the three-dimensional shaped object is reduced. However, when a part of the molten material enters the fine pores, in a layer of the molten material formed on the stage, a line width of the molten material differs between a part on the fine pores and a part away from the fine pores, and unevenness is generated, so that dimensional accuracy of the three-dimensional shaped object may be reduced.

SUMMARY

According to one embodiment of the present disclosure, a method for manufacturing a three-dimensional shaped object is provided. The method for manufacturing a three-dimensional shaped object includes: a first shaping step of forming a first layer in contact with a stage provided with a recessed portion by changing a relative position between a discharge unit and the stage while discharging a molten material from the discharge unit toward the stage; and a second shaping step of stacking one or more layers on the first layer by changing the relative position between the discharge unit and the stage while discharging the molten material from the discharge unit toward the first layer. The stage has a first region including a region on the recessed portion and a second region different from the first region, and in the first shaping step, the first layer is formed by making a first supply amount which is a supply amount of the molten material supplied from the discharge unit to the first region per unit area larger than a second supply amount which is a supply amount of the molten material supplied from the discharge unit to the second region per unit area.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a schematic configuration of a three-dimensional shaping device according to a first embodiment.

FIG. 2 is a schematic perspective view showing a configuration of a flat screw on a groove forming surface side.

FIG. 3 is a top view showing a configuration of a barrel on a screw facing surface side.

FIG. 4 is a perspective view showing a configuration of a valve portion of a discharge amount adjusting mechanism.

FIG. 5 is a first diagram showing an operation of the valve portion of the discharge amount adjusting mechanism.

FIG. 6 is a second diagram showing an operation of the valve portion of the discharge amount adjusting mechanism.

FIG. 7 is a top view showing a configuration of a stage on a shaping surface side.

FIG. 8 is a flowchart showing a method for manufacturing the three-dimensional shaped object according to the first embodiment.

FIG. 9 is a diagram showing a state of a first shaping step according to the first embodiment.

FIG. 10 is a diagram showing a state of a second shaping step according to the first embodiment.

FIG. 11 is a flowchart showing contents of the first shaping step according to the first embodiment.

FIG. 12 is a diagram showing a first region and a second region according to the first embodiment.

FIG. 13 is a graph showing a relationship between a position on the stage and a supply amount of a shaping material.

FIG. 14 is a diagram showing a first layer of the three-dimensional shaped object according to a comparative example.

FIG. 15 is a diagram showing a schematic configuration of a three-dimensional shaping device according to a second embodiment.

FIG. 16 is a flowchart showing contents of a first shaping step according to the second embodiment.

FIG. 17 is a diagram showing a schematic configuration of a three-dimensional shaping device according to a third embodiment.

FIG. 18 is a flowchart showing contents of a first shaping step according to the third embodiment.

FIG. 19 is a top view showing a configuration of a stage on a shaping surface side according to another embodiment.

FIG. 20 is a diagram showing a cross section of a recessed portion of the stage according to another embodiment.

FIG. 21 is a graph showing a relationship between a position on the stage and a supply amount of a shaping material according to another embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS A. First Embodiment

FIG. 1 is a diagram showing a schematic configuration of a three-dimensional shaping device 100 according to a first embodiment. FIG. 1 shows arrows along X, Y, and Z directions orthogonal to each other. The X direction and the Y direction are directions along a horizontal direction, and the Z direction is a direction along a vertical direction. In other figures, the arrows along the X, Y, and Z directions are appropriately shown. The X, Y, Z directions in FIG. 1 and the X, Y, Z directions in other figures represent the same direction.

The three-dimensional shaping device 100 according to the present embodiment includes a shaping unit 200, a stage 300, a moving mechanism 400, and a control unit 500. Under control of the control unit 500, the three-dimensional shaping device 100 shapes a three-dimensional shaped object having a desired shape on a shaping surface 311 by driving the moving mechanism 400 to change a relative position between a nozzle hole 69 and the stage 300 while discharging a shaping material from the nozzle hole 69 provided in the shaping unit 200 toward the stage 300. The shaping material is sometimes called a molten material. A detailed configuration of the shaping unit 200 will be described later.

The stage 300 includes a plate portion 310 and a base portion 320 that supports the plate portion 310. The plate portion 310 has the shaping surface 311 facing the nozzle hole 69. The shaping material discharged from the nozzle hole 69 is stacked on the shaping surface 311. The stage 300 includes a recessed portion 315. The recessed portion 315 means a portion in which the shaping surface 311 is recessed by providing a recess or a through hole in the plate portion 310. In the present embodiment, a plurality of through holes having opening portions on the shaping surface 311 are provided in the plate portion 310, and by combining the plate portion 310 and the base portion 320, a plurality of recessed portions 315 in which the shaping surface 311 is recessed are formed in the stage 300. A specific configuration of the stage 300 on a shaping surface 311 side will be described later.

The moving mechanism 400 changes the relative position between the nozzle hole 69 and the shaping surface 311. According to the present embodiment, the moving mechanism 400 changes the relative position between the nozzle hole 69 and the shaping surface 311 by moving the stage 300 with respect to the shaping unit 200. The moving mechanism 400 according to the present embodiment is implemented by a three-axis positioner that moves the stage 300 in three axial directions of the X, Y, and Z directions by drive forces of three motors. Each motor is driven under the control of the control unit 500. The moving mechanism 400 may be configured to change the relative position between the nozzle hole 69 and the shaping surface 311 by moving the shaping unit 200 without moving the stage 300, instead of moving the stage 300. In addition, the moving mechanism 400 may be configured to change the relative position between the nozzle hole 69 and the shaping surface 311 by moving both the stage 300 and the shaping unit 200.

The control unit 500 is implemented by a computer including one or more processors, a main storage device, and an input and output interface for inputting and outputting signals to and from an outside. According to the present embodiment, the control unit 500 controls operations of the shaping unit 200 and the moving mechanism 400 by the processor executing a program or a command read in the main storage device, so as to execute a shaping process for shaping a three-dimensional shaped object. The operations include changing a three-dimensional relative position between the shaping unit 200 and the stage 300. The control unit 500 may be implemented by a combination of a plurality of circuits instead of a computer.

The shaping unit 200 includes a material supply unit 20 that is a material supply source, a melting unit 30 that melts a material supplied from the material supply unit 20 into a shaping material, a discharge unit 60 having the nozzle hole 69 that discharges the shaping material supplied from the melting unit 30, and a discharge amount adjusting mechanism 70 that adjusts a flow rate of the shaping material discharged from the nozzle hole 69.

A material in a state of pellets, powder, or the like is accommodated in the material supply unit 20. According to the present embodiment, a pellet-shaped ABS resin is used as the material. The material supply unit 20 according to the present embodiment is implemented by a hopper. Below the material supply unit 20, a supply path 22 that couples the material supply unit 20 and the melting unit 30 is provided. The material supply unit 20 supplies the material to the melting unit 30 via the supply path 22.

The melting unit 30 includes a screw case 31, a drive motor 32, a flat screw 40, and a barrel 50. The melting unit 30 melts at least a part of a solid-state material supplied from the material supply unit 20, converts the material into a paste-shaped shaping material having fluidity, and supplies the material to the discharge unit 60.

The screw case 31 is a housing for accommodating the flat screw 40. The barrel 50 is fixed to a lower surface of the screw case 31, and the flat screw 40 is accommodated in a space surrounded by the screw case 31 and the barrel 50. The drive motor 32 is fixed to an upper surface of the screw case 31. A rotation shaft of the drive motor 32 is coupled to an upper surface 41 side of the flat screw 40. The drive motor 32 is driven under the control of the control unit 500.

The flat screw 40 has a substantially columnar shape whose height in a direction along a central axis RX is smaller than a diameter thereof. The flat screw 40 is disposed in the screw case 31 such that the central axis RX is parallel to the Z direction. The flat screw 40 rotates around the central axis RX in the screw case 31 due to a torque generated by the drive motor 32. The flat screw 40 includes a groove forming surface 42 at which groove portions 45 are formed on a side opposite to the upper surface 41 in the direction along the central axis RX. A specific configuration of the flat screw 40 on a groove forming surface 42 side will be described later.

The barrel 50 is disposed below the flat screw 40. The barrel 50 includes a screw facing surface 52 that faces the groove forming surface 42 of the flat screw 40. The barrel 50 is provided with a communication hole 56 that communicates with the discharge unit 60 on the central axis RX of the flat screw 40. The barrel 50 is provided with a heater 58 at a position facing the groove portion 45 of the flat screw 40. A temperature of the heater 58 is controlled by the control unit 500. A specific configuration of the barrel 50 on a screw facing surface 52 side will be described later.

The discharge unit 60 is fixed to a lower surface of the barrel 50. The discharge unit 60 includes a supply flow path 62 and a nozzle 61. The supply flow path 62 communicates between the melting unit 30 and the nozzle 61, and supplies the shaping material from the melting unit 30 to the nozzle 61.

The supply flow path 62 includes a first supply port 65, a cross hole 66, and a second supply port 67. The first supply port 65 extends in the vertical direction. An upper end of the first supply port 65 is coupled to the communication hole 56 of the barrel 50, and a lower end of the first supply port 65 is coupled to the cross hole 66. The cross hole 66 extends in the horizontal direction. The cross hole 66 accommodates a valve portion 73 of the discharge amount adjusting mechanism 70 described later. The second supply port 67 extends in the vertical direction. An upper end of the second supply port 67 is coupled to the cross hole 66, and a lower end of the second supply port 67 is coupled to the nozzle 61. The shaping material supplied from the communication hole 56 of the barrel 50 to the first supply port 65 flows in an order of the cross hole 66, the second supply port 67, and the nozzle 61.

The nozzle 61 is provided with a nozzle flow path 68 and the nozzle hole 69. The nozzle flow path 68 is a flow path provided in the nozzle 61. The nozzle flow path 68 is coupled to the second supply port 67. The nozzle hole 69 is a portion in which a flow path cross section provided at an end portion on a side of the nozzle flow path 68 communicating with atmosphere is reduced. The shaping material supplied from the second supply port 67 to the nozzle flow path 68 is discharged from the nozzle hole 69. According to the present embodiment, an opening shape of the nozzle hole 69 is a circle. A diameter of an opening portion of the nozzle hole 69 is called a nozzle diameter Dn. The opening shape of the nozzle hole 69 is not limited to a circle, and may be, for example, a square or a polygon other than the square.

The discharge amount adjusting mechanism 70 includes the valve portion 73 disposed in the cross hole 66, and a valve drive unit 79 configured to rotate the valve portion 73. The valve drive unit 79 is implemented by an actuator such as a stepping motor, and rotates the valve portion 73 in the cross hole 66 under the control of the control unit 500. The discharge amount adjusting mechanism 70 adjusts a flow rate of the shaping material discharged from the nozzle hole 69 by rotating the valve portion 73 to adjust the flow rate of the shaping material flowing from the first supply port 65 to the second supply port 67. The flow rate of the shaping material discharged from the nozzle holes 69 is also called a discharge amount. A specific configuration of the discharge amount adjusting mechanism 70 will be described later.

FIG. 2 is a schematic perspective view showing the configuration of the flat screw 40 on the groove forming surface 42 side. In FIG. 2, a position of the central axis RX of the flat screw 40 is shown by a dashed line. As described with reference to FIG. 1, the groove portion 45 is provided in the groove forming surface 42.

A central portion 47 of the groove forming surface 42 of the flat screw 40 is implemented as a recess to which one end of the groove portion 45 is coupled. The central portion 47 faces the communication hole 56 of the barrel 50 shown in FIG. 1. The central portion 47 crosses the central axis RX.

The groove portion 45 of the flat screw 40 forms a so-called scroll groove. The groove portion 45 extends spirally from the central portion 47 toward an outer periphery of the flat screw 40 so as to draw an arc. The groove portion 45 may be configured to extend spirally. The groove forming surface 42 is provided with ridge portions 46 that form a side wall portion of the respective groove portions 45 and extends along the respective groove portions 45.

The groove portion 45 extends to a material introduction port 44 formed in a side surface 43 of the flat screw 40. The material introduction port 44 is a portion that receives the material supplied via the supply path 22 of the material supply unit 20.

FIG. 2 shows an example of the flat screw 40 including three groove portions 45 and three ridge portions 46. The number of the groove portions 45 or the ridge portions 46 provided on the flat screw 40 is not limited to three. The flat screw 40 may be provided with only one groove portion 45, or may be provided with two or more groove portions 45. Any number of the ridge portions 46 may be provided in accordance with the number of the groove portions 45.

FIG. 2 illustrates an example of the flat screw 40 in which the material introduction port 44 is formed at three places. The number of the material introduction port 44 provided in the flat screw 40 is not limited to three. In the flat screw 40, the material introduction port 44 may be provided at only one place, or may be provided at two or more places.

FIG. 3 is a top view showing the configuration of the barrel 50 on the screw facing surface 52 side. As described above, the communication hole 56 that communicates with the discharge unit 60 is formed at a center of the screw facing surface 52. A plurality of guide grooves 54 are formed around the communication hole 56 in the screw facing surface 52. The guide groove 54 has one end coupled to the communication hole 56, and extends spirally from the communication hole 56 toward an outer periphery of the screw facing surface 52. The guide groove 54 has a function of guiding the shaping material to the communication hole 56.

FIG. 4 is a perspective view showing a configuration of the valve portion 73 of the discharge amount adjusting mechanism 70. As described above, the discharge amount adjusting mechanism 70 includes the valve portion 73 disposed in the cross hole 66. The valve portion 73 has a columnar shape centered on a central axis AX. The valve portion 73 is provided with a cutout portion 75 by cutting out a part of a columnar outer periphery in a half-moon shape. An operation portion 77 is provided at an end portion of the valve portion 73 on a −Y direction side. The valve drive unit 79 is coupled to the operation portion 77. When a torque from the valve drive unit 79 is applied to the operation portion 77, the valve portion 73 rotates. The cutout portion 75 may be called a flow passage.

FIG. 5 is a first diagram showing an operation of the valve portion 73 of the discharge amount adjusting mechanism 70. FIG. 6 is a second diagram showing an operation of the valve portion 73 of the discharge amount adjusting mechanism 70. As shown in FIG. 5, when the valve portion 73 rotates such that the cutout portion 75 is located upward, the second supply port 67 is closed by the valve portion 73, and a flow of the shaping material from the first supply port 65 to the second supply port 67 is blocked. On the other hand, as shown in FIG. 6, when the valve portion 73 rotates such that the cutout portion 75 faces a +X direction or a −X direction, the first supply port 65 communicates with the second supply port 67, and the shaping material flows from the first supply port 65 to the second supply port 67 at a maximum flow rate. The discharge amount adjusting mechanism 70 changes a flow path cross-sectional area between the first supply port 65 and the second supply port 67 in accordance with the rotation of the valve portion 73, and changes a flow rate of the shaping material flowing from the first supply port 65 to the second supply port 67. The discharge amount adjusting mechanism 70 may be implemented by, for example, a gate valve, a globe valve, or a ball valve, instead of the valve portion 73 described above.

FIG. 7 is a top view showing the configuration of the stage 300 on the shaping surface 311 side. According to the present embodiment, the plate portion 310 is implemented by a square plate-shaped member. The plate portion 310 has the shaping surface 311 on an upper surface on which shaping materials are stacked. The plate portion 310 is provided with a plurality of recessed portions 315 having opening portions on the shaping surface 311. The opening portions of the plurality of recessed portions 315 are arranged in a grid on the shaping surface 311. On the shaping surface 311, a plurality of recessed portions 315 are arranged at regular intervals along the X direction, and a plurality of recessed portions 315 are arranged at regular intervals along the Y direction. The plate portion 310 may be implemented by a circular plate-shaped member instead of the square plate-shaped member.

An opening shape of the recessed portion 315 is a circle. Diameters Dh of the opening portions of respective recessed portions 315 are set to be the same. The diameter Dh of the opening portion of the recessed portion 315 is set to be the same as the nozzle diameter Dn. As a material of the plate portion 310, for example, epoxy glass can be used. The recessed portion 315 can be provided by performing a cutting process on the plate portion 310. The opening shape of the recessed portion 315 may be not a circle but a square or a polygon other than the square. The diameter Dh of the opening portion of the recessed portion 315 may be set larger than the nozzle diameter Dn, or may be set smaller than the nozzle diameter Dn. The diameter Dh of the opening portion of the recessed portion 315 is preferably set to be twice the nozzle diameter Dn or less.

FIG. 8 is a flowchart showing a method for manufacturing the three-dimensional shaped object according to the present embodiment. When a predetermined start operation is performed by a user on an operation panel provided in the three-dimensional shaping device 100 or a computer connected to the three-dimensional shaping device 100, the shaping process is performed by the control unit 500. By executing the shaping process, the three-dimensional shaping device 100 starts manufacturing the three-dimensional shaped object.

First, in a data acquisition step of step S110, the control unit 500 acquires shaping data for shaping the three-dimensional shaped object. The shaping data is acquired from a computer or a recording medium connected to the three-dimensional shaping device 100, for example. The shaping data is data for shaping the three-dimensional shaped object by the three-dimensional shaping device 100. The shaping data represents various information such as a movement path of the nozzle hole 69 with respect to the stage 300, a target speed of movement of the nozzle hole 69 with respect to the stage 300, a target flow rate of the shaping material discharged from the nozzle hole 69 during movement, a target rotation speed of the drive motor 32 for rotating the flat screw 40, a target temperature of the heater 58 provided in the barrel 50, and a target rotation angle of the valve portion 73 of the discharge amount adjusting mechanism 70. Shape data representing a shape of the three-dimensional shaped object created using three-dimensional CAD software or three-dimensional CG software is read into, for example, slicer software on a computer connected to the three-dimensional shaping device 100 to create the shaping data. Data in an STL format or an AMF format can be used for the shape data read into the slicer software.

Next, in a material generation step of step S120, the control unit 500 starts generating a shaping material. The control unit 500 controls the rotation of the flat screw and the temperature of the heater 58 provided in the barrel 50 according to the acquired shaping data, so as to melt the material and generate the shaping material. By the rotation of the flat screw 40, the material supplied from the material supply unit 20 is introduced into the groove portion 45 from the material introduction port 44 of the flat screw 40. The material introduced into the groove portion 45 is transported along the groove portion 45 to the central portion 47. The material transported in the groove portion 45 is sheared by a relative rotation of the flat screw 40 and the barrel 50, and at least a portion of the material is melted by heating with the heater 58 to become the paste-shaped shaping material having fluidity. The shaping material collected in the central portion 47 is supplied to the nozzle 61 via the communication hole 56 by an internal pressure generated in the central portion 47. The shaping material continues to be generated while a first shaping step and a second shaping step are performed.

FIG. 9 is a diagram showing a state of the first shaping step according to the present embodiment. FIG. 9 shows a state where a first layer LY1 of the three-dimensional shaped object OB is formed as viewed from a side surface of the stage 300. With reference to FIGS. 8 and 9, in the first shaping step of step S130, the control unit 500 forms the first layer LY1 in contact with the stage 300 by changing the relative position between the nozzle hole 69 and the stage 300 while discharging the shaping material from the nozzle hole 69 of the discharge unit 60 toward the stage 300 provided with the recessed portion 315. According to the present embodiment, the control unit 500 forms the first layer LY1 in contact with the stage 300 by controlling the moving mechanism 400 to change the relative position between the nozzle hole 69 and the stage 300 while controlling the discharge amount adjusting mechanism 70 to discharge the shaping material from the nozzle hole 69 toward the stage 300 according to the shaping data. A part of the shaping material discharged from the nozzle hole 69 toward the stage 300 enters the recessed portion 315. A distance from a tip of the shaping material entering the recessed portion 315 to the shaping surface 311 is called a depth H1. More detailed contents of the first shaping step will be described later.

FIG. 10 is a diagram showing a state of the second shaping step according to the present embodiment. FIG. 10 shows, as an example, a state where a second layer LY2 to a fifth layer LY5 of the three-dimensional shaped object OB are formed as viewed from the side surface of the stage 300. With reference to FIGS. 8 and 10, in the second shaping step of step S140, the control unit 500 stacks one or more layers on the first layer LY1 by changing the relative position between the nozzle hole 69 and the stage 300 while discharging the shaping material from the nozzle hole 69 toward the first layer LY1. According to the present embodiment, the control unit 500 stacks one or more layers on the first layer LY1 by controlling the moving mechanism 400 to change the relative position between the nozzle hole 69 and the stage 300 while controlling the discharge amount adjusting mechanism 70 to discharge the shaping material from the nozzle hole 69 toward the first layer LY1 according to the shaping data. In this way, the three-dimensional shaped object OB in which a plurality of layers are stacked is manufactured.

FIG. 11 is a flowchart showing contents of the first shaping step according to the present embodiment. According to the present embodiment, first, in step S210, the control unit 500 sets a first region RG1 and a second region RG2 on the stage 300 along the shaping surface 311. A region on the stage 300 and including a region on the recessed portion 315 is set as the first region RG1. A region on the stage 300 and different from the first region RG1 is set as the second region RG2.

FIG. 12 is a diagram showing the first region RG1 and the second region RG2 according to the present embodiment. FIG. 12 shows a part of the stage 300 as viewed from above. In FIG. 12, a direction in which the nozzle hole 69 moves with respect to the stage 300 is shown by an arrow. The shaping material discharged from the nozzle hole is linearly deposited on the stage 300 along the direction in which the nozzle hole 69 moves. A target value of a width of the shaping material linearly deposited is called a target line width Wm. According to the present embodiment, the control unit 500 sets, as the first region RG1, a region in which a region on the recessed portion 315 and a region outside an edge of the recessed portion 315 within a distance half the target line width Wm of the shaping material from the edge of the recessed portion 315 are combined. That is, the control unit 500 uses a radius Rh of the opening portion of the recessed portion 315 and the target line width Wm to set the first region RG1 as a region inside a circle whose radius Ra is represented by the following equation (1). Ra=Rh+Wm/2  (1)

The target line width Wm is represented in the shaping data. Information about a position of a center point CP of the recessed portion 315 along the shaping surface 311 and the radius Rh of the opening portion of the recessed portion 315 can be stored in advance in a storage device of the control unit 500. FIG. 12 shows a state where one line of the shaping material is deposited on the stage 300, whereas a plurality of lines of the shaping material are two-dimensionally deposited on the stage 300 to form the first layer LY1 according to the shaping data.

With reference to FIG. 11, in step S220, the control unit 500 determines whether to supply the shaping material to the first region RG1. When it is determined to supply the shaping material to the first region RG1, in step S230, the control unit 500 sets a supply amount of the shaping material supplied from the nozzle hole 69 to the first region RG1 per unit area to be larger than a supply amount according to the shaping data, and forms the first layer LY1. On the other hand, when it is determined not to supply the shaping material to the first region RG1, that is, when it is determined to supply the shaping material to the second region RG2, in step S240, the control unit 500 sets a supply amount of the shaping material supplied from the nozzle hole 69 to the second region RG2 per unit area to be the same as the supply amount according to the shaping data, and forms the first layer LY1. The supply amount of the shaping material supplied from the nozzle hole 69 to the first region RG1 per unit area is called a first supply amount S1, and the supply amount of the shaping material supplied from the nozzle hole 69 to the second region RG2 per unit area is called a second supply amount S2. The first supply amount S1 is set to be larger than the second supply amount S2. The control unit 500 sets the first supply amount S1 such that an amount of the shaping material supplied to the entire first region RG1 is equal to an amount of the shaping material entering the recessed portion 315. The amount of the shaping material entering the recessed portion 315 can be calculated by a product of an opening area of the recessed portion 315 and the target value of the entering depth H1 of the shaping material entering the recessed portion 315. The target value of the entering depth H1 can be set in advance by a test performed in advance. The target value of the entering depth H1 can be set according to the opening area of the recessed portion 315, a temperature of the stage 300, a temperature of the shaping material discharged from the nozzle hole 69, and a type of the shaping material.

According to the present embodiment, the control unit 500 makes the first supply amount S1 larger than the second supply amount S2 by controlling the discharge amount adjusting mechanism 70 to make a first flow rate which is a flow rate of the shaping material discharged from the nozzle hole 69 toward the first region RG1 larger than a second flow rate which is a flow rate of the shaping material discharged from the nozzle hole 69 toward the second region RG2. Discharging the shaping material toward the first region RG1 means discharging the shaping material from the nozzle hole 69 at timing when a center of the nozzle hole 69 is located above the first region RG1. Discharging the shaping material toward the second region RG2 means discharging the shaping material from the nozzle hole 69 at timing when the center of the nozzle hole 69 is located above the second region RG2.

FIG. 13 is a graph schematically showing a relationship between the position on the stage 300 and the supply amount of the shaping material according to the present embodiment. A horizontal axis represents the position on the stage 300. A vertical axis represents the supply amount of the shaping material supplied on the stage 300 per unit area. As described above, according to the present embodiment, the shaping material is supplied to the first region RG1 with the first supply amount S1, and the shaping material is supplied to the second region RG2 with the second supply amount S2. The first supply amount S1 is a constant amount, and the second supply amount S2 is a constant amount.

With reference to FIG. 11, thereafter, in step S250, the control unit 500 determines whether the formation of the first layer LY1 is completed. The control unit 500 can determine whether the formation of the first layer LY1 is completed using the shaping data. When it is determined that the formation of the first layer LY1 is not completed, the control unit 500 returns the processing to step S220, and continues the formation of the first layer LY1. On the other hand, when it is determined that the formation of the first layer LY1 is completed, the control unit 500 ends the first shaping step and starts the second shaping step as shown in FIG. 8.

With reference to FIGS. 9 and 10, according to the present embodiment, by discharging the shaping material from the nozzle hole 69 toward the stage 300 including the recessed portion 315, a part of the shaping material deposited on the stage 300, that is, a part of the first layer LY1 of the three-dimensional shaped object OB enters the recessed portion 315 and is cured. Therefore, the three-dimensional shaped object OB is less likely to peel off from the stage 300 due to an anchor effect, and warpage of the three-dimensional shaped object OB is reduced.

FIG. 14 is a diagram showing the first layer LY1 of a three-dimensional shaped object OB2 according to a comparative example. When the first supply amount S1 and the second supply amount S2 are the same, as shown in FIG. 14, an upper surface of the first layer LY1 on the first region RG1 is lower than an upper surface of the first layer LY1 on the second region RG2, and unevenness is generated on the upper surface of the first layer LY1. When the first supply amount S1 and the second supply amount S2 are the same, a line width of the shaping material linearly deposited on the first region RG1 to form the first layer LY1 becomes narrower than a line width of the shaping material linearly deposited on the second region RG2, and voids are generated in the first layer LY1.

According to the three-dimensional shaping device 100 of the present embodiment described above, the control unit 500 forms the first layer LY1 which is a portion of the three-dimensional shaped object OB in contact with the stage 300 by setting, in the first shaping step, the first supply amount S1 which is the supply amount of the shaping material supplied from the nozzle hole 69 to the first region RG1 per unit area to be larger than the second supply amount S2 which is the supply amount of the shaping material supplied from the nozzle hole 69 to the second region RG2 per unit area. Therefore, even when a part of the shaping material supplied on the stage 300 enters the recessed portion 315, the unevenness on the upper surface of the first layer LY1 and the voids in the first layer LY1 due to the narrow line width of the shaping material are reduced. Since the unevenness on the upper surface of the first layer LY1 is reduced, the unevenness on the upper surface of the layer stacked on the first layer LY1 is reduced. Therefore, it is possible to improve dimensional accuracy of the three-dimensional shaped object OB manufactured by stacking the shaping materials on the stage 300 including the recessed portion 315.

According to the present embodiment, the control unit 500 makes the first supply amount S1 larger than the second supply amount S2 by controlling the discharge amount adjusting mechanism 70 to make the flow rate of the shaping material discharged toward the first region RG1 larger than the flow rate of the shaping material discharged toward the second region RG2. Therefore, the first supply amount S1 can be made larger than the second supply amount S2 by simple control.

According to the present embodiment, the radius Rh of the recessed portion 315 and the target line width Wm are used to set the first region RG1 as a region inside a circle whose radius Ra is represented by the equation (1). Therefore, since it is possible to reduce a shortage of the shaping material supplied to a region on the recessed portion 315 and an excessive supply of the shaping material to a region away from the recessed portion 315, it is possible to more reliably reduce the unevenness on the upper surface of the first layer LY1.

According to the present embodiment, a pellet-shaped ABS resin is used as the material, whereas as a material used in the shaping unit 200, for example, a material for shaping a three-dimensional shaped object using various materials such as a material having thermoplasticity, a metal material, and a ceramic material as a main material can also be used. Here, the “main material” means a central material for forming a shape of the three-dimensional shaped object, and a material occupying a content of 50% by weight or more in the three-dimensional shaped object. The above shaping materials include those in which main materials are melted alone, and those in which some of the contained components are melted together with the main materials to form a paste.

When a material having thermoplasticity is used as the main material, a shaping material is generated by plasticizing the material in the melting unit 30. The “plasticizing” means that a material having thermoplasticity is heated and melted. The “melting” also means that a material having thermoplasticity is softened by being heated to a temperature equal to or higher than a glass transition point thereof, and exhibits fluidity.

As a material having thermoplasticity, for example, a thermoplastic resin material obtained by combining one or more of the following can be used.

Example of Thermoplastic Resin Material

General-purpose engineering plastics such as a polypropylene resin (PP), a polyethylene resin (PE), a polyacetal resin (POM), a polyvinyl chloride resin (PVC), a polyamide resin (PA), an acrylonitrile-butadiene-styrene resin (ABS), a polylactic acid resin (PLA), a polyphenylene sulfide resin (PPS), polycarbonate (PC), modified polyphenylene ether, polybutylene terephthalate, and polyethylene terephthalate, and engineering plastics such as polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, polyimide, polyamideimide, polyetherimide, and polyetheretherketone (PEEK)

The material having thermoplasticity may contain pigments, metals, ceramics, and an additive such as a wax, a flame retardant, an antioxidant, and a heat stabilizer. The material having thermoplasticity is plasticized and melted by the rotation of the flat screw 40 and the heating with the heater 58 in the melting unit 30. After the shaping material thus generated is discharged from the nozzle hole 69, the shaping material is cured due to a reduction in temperature.

It is desirable that the material having thermoplasticity is discharged from the nozzle holes 69 in a state where the material is heated to a temperature equal to or higher than the glass transition point thereof and is in a state of being completely melted. The “state of being completely melted” means a state where a non-melted material having thermoplasticity does not exist, and means a state where, for example, when a pellet-shaped thermoplastic resin is used as the material, a pellet-shaped solid does not remain.

In the shaping unit 200, for example, the following metal material may be used as a main material instead of the above material having thermoplasticity. In this case, it is desirable that a component to be melted at the time of forming the shaping material is mixed with a powder material obtained by converting the following metal material into a powder, and then the mixture is charged into the melting unit 30.

Example of Metal Material

A single metal of magnesium (Mg), iron (Fe), cobalt (Co) or chromium (Cr), aluminum (Al), titanium (Ti), copper (Cu), and nickel (Ni), or an alloy containing one or more of these metals

Example of Alloy

Maraging steel, stainless steel, cobalt chrome molybdenum, titanium alloy, nickel alloy, aluminum alloy, cobalt alloy, and cobalt chromium alloy

In the shaping unit 200, a ceramic material can be used as a main material instead of the above metal material. As the ceramic material, for example, oxide ceramics such as silicon dioxide, titanium dioxide, aluminum oxide, and zirconium oxide, and non-oxide ceramics such as aluminum nitride can be used. When the above metal material or ceramic material is used as the main material, the shaping material disposed on the stage 300 may be cured by, for example, sintering with laser irradiation or warm air.

The powder material of the metal material or the ceramic material charged into the material supply unit 20 may be a mixed material obtained by mixing a plurality of types of powders of a single metal powder, an alloy powder, and a ceramic material powder. The powder material of the metal material or the ceramic material may be coated with, for example, the thermoplastic resin shown above or another thermoplastic resin. In this case, the thermoplastic resin may be melted in the melting unit 30 to exhibit fluidity.

For example, the following solvents can be added to the powder material of the metal material or the ceramic material charged into the material supply unit 20. The solvent can be used alone or in combination of two or more selected from the following.

Example of Solvent

Water, (poly)alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether, acetate esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, and iso-butyl acetate, aromatic hydrocarbons such as benzene, toluene, and xylene, ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, ethyl-n-butyl ketone, diisopropyl ketone, and acetylacetone, alcohols such as ethanol, propanol, and butanol, tetraalkylammonium acetates, sulfoxide-based solvents such as dimethyl sulfoxide and diethyl sulfoxide, pyridine-based solvents such as pyridine, γ-picoline, and 2,6-lutidine, tetraalkylammonium acetates (such as tetrabutylammonium acetate), and ionic liquids such as butyl carbitol acetate

In addition, for example, the following binders can be added to the powder material of the metal material or the ceramic material charged into the material supply unit 20.

Example of Binder

Acrylic resin, epoxy resin, silicone resin, cellulose resin or other synthetic resins, or polylactic acid (PLA), polyamide (PA), polyphenylene sulfide (PPS), polyetheretherketone (PEEK) or other thermoplastic resins

B. Second Embodiment

FIG. 15 is a diagram showing a schematic configuration of a three-dimensional shaping device 100 b according to a second embodiment. The three-dimensional shaping device 100 b according to the second embodiment is different from the first embodiment in that a hole detection unit 90 is provided in a shaping unit 200 b. Other configurations are the same as those of the first embodiment shown in FIG. 1 unless otherwise specified.

The hole detection unit 90 is provided on a lower surface of the discharge unit 60 adjacent to the nozzle 61. The hole detection unit 90 detects a position and a size of the recessed portion 315 by detecting unevenness of the shaping surface 311 of the stage 300. According to the present embodiment, the hole detection unit 90 is implemented by a camera 91 that images the shaping surface 311 of the stage 300. According to the present embodiment, two cameras 91 are provided sandwiching the nozzle 61 so as to prevent a blind spot from being generated by being blocked by the nozzle 61 and the shaping material discharged from the nozzle hole 69. An image of the stage 300 imaged by the camera 91 is transmitted to the control unit 500. The control unit 500 acquires the position and the size of the recessed portion 315 on the stage 300 by analyzing the image imaged by the camera 91. The hole detection unit 90 may be implemented by one camera 91, or may be implemented by three or more cameras 91. The hole detection unit 90 may be implemented by a laser displacement meter or a step meter instead of the camera 91.

FIG. 16 is a flowchart showing contents of a first shaping step according to the present embodiment. First, in step S305, the control unit 500 uses the hole detection unit 90 to acquire the position and size of the recessed portion 315 provided in a front of the stage 300 in a direction in which the nozzle hole 69 moves. Next, in step S310, the control unit 500 uses the acquired position and size of recessed portion 315 to set the first region RG1 and the second region RG2. A range of the first region RG1 is set to the same range as in the first embodiment.

Thereafter, in step S320, the control unit 500 determines whether to supply the shaping material to the first region RG1. When it is determined to supply the shaping material to the first region RG1, in step S330, the control unit 500 sets a supply amount of the shaping material supplied from the nozzle hole 69 to the first region RG1 per unit area as the first supply amount S1, and forms the first layer LY1. On the other hand, when it is determined not to supply the shaping material to the first region RG1, that is, when it is determined to supply the shaping material to the second region RG2, in step S340, the control unit 500 sets a supply amount of the shaping material supplied from the nozzle hole 69 to the second region RG2 per unit area as the second supply amount S2, and forms the first layer LY1. The first supply amount S1 is set to be larger than the second supply amount S2. As in the first embodiment, the control unit 500 makes the first supply amount S1 larger than the second supply amount S2 by controlling the discharge amount adjusting mechanism 70 to make a first flow rate which is a flow rate of the shaping material discharged from the nozzle hole 69 toward the first region RG1 larger than a second flow rate which is a flow rate of the shaping material discharged from the nozzle hole 69 toward the second region RG2.

After step S330 or step S340, the control unit 500 determines whether the formation of the first layer LY1 is completed. The control unit 500 can determine whether the formation of the first layer LY1 is completed using the shaping data. When it is determined that the formation of the first layer LY1 is not completed, the control unit 500 returns the processing to step S305, and continues the formation of the first layer LY1. On the other hand, when it is determined that the formation of the first layer LY1 is completed, the control unit 500 ends the first shaping step and starts the second shaping step as shown in FIG. 8. The contents of the data acquisition step, the material generation step, and the second shaping step shown in FIG. 8 are the same as in the first embodiment.

According to the three-dimensional shaping device 100 b of the present embodiment described above, the control unit 500 can use the hole detection unit 90 to acquire the position and the size of the recessed portion 315. Therefore, the first region RG1 can be set even when the position and size of the recessed portion 315 are not stored in advance.

C. Third Embodiment

FIG. 17 is a diagram showing a schematic configuration of a three-dimensional shaping device 100 c according to a third embodiment. The three-dimensional shaping device 100 c according to the third embodiment is different from the first embodiment in that a line width measuring unit 95 is provided in a shaping unit 200 c. Other configurations are the same as those of the first embodiment shown in FIG. 1 unless otherwise specified.

The line width measuring unit 95 is provided on the lower surface of the discharge unit 60 adjacent to the nozzle 61. The line width measuring unit 95 measures a line width of the shaping material linearly deposited on the stage 300. According to the present embodiment, the line width measuring unit 95 is implemented by a camera 91 c. According to the present embodiment, two cameras 91 c are provided sandwiching the nozzle 61 so as to prevent a blind spot from being generated by the nozzle 61 and the shaping material discharged from the nozzle hole 69. An image imaged by the camera 91 c is transmitted to the control unit 500. The control unit 500 acquires the line width of the shaping material by analyzing the image imaged by the camera 91 c. The line width measuring unit 95 may be implemented by one camera 91 c, or may be implemented by three or more cameras 91 c.

FIG. 18 is a flowchart showing contents of a first shaping step according to the third embodiment. First, in step S410, the control unit 500 sets the first region RG1 and the second region RG2 on the stage 300 along the shaping surface 311. Next, in step S420, the control unit 500 determines whether to supply the shaping material to the first region RG1. When it is determined to supply the shaping material to the first region RG1, in step S430, the control unit 500 sets a supply amount of the shaping material supplied from the nozzle hole 69 to the first region RG1 per unit area as the first supply amount S1, and forms the first layer LY1. On the other hand, when it is determined not to supply the shaping material to the first region RG1, that is, when it is determined to supply the shaping material to the second region RG2, in step S440, the control unit 500 sets a supply amount of the shaping material supplied from the nozzle hole 69 to the second region RG2 per unit area as the second supply amount S2, and forms the first layer LY1. The first supply amount S1 is set to be larger than the second supply amount S2. As in the first embodiment, the control unit 500 makes the first supply amount S1 larger than the second supply amount S2 by controlling the discharge amount adjusting mechanism 70 to make a first flow rate which is a flow rate of the shaping material discharged from the nozzle hole 69 toward the first region RG1 larger than a second flow rate which is a flow rate of the shaping material discharged from the nozzle hole 69 toward the second region RG2.

In step S450, the control unit 500 uses the line width measuring unit 95 to acquire a line width of the shaping material linearly deposited on the stage 300. In step S460, the control unit 500 determines whether the acquired line width is smaller than target line width Wm. The target line width Wm can be acquired using the shaping data. When it is determined that the acquired line width is smaller than the target line width Wm, in step S470, the control unit 500 corrects the supply amount of the shaping material such that the line width of the shaping material discharged from the nozzle hole 69 and deposited on the stage 300 in step S430 or step S440 approaches the target line width Wm. According to the present embodiment, the control unit 500 corrects the supply amount of the shaping material by correcting the flow rate of the shaping material discharged from the nozzle hole 69. On the other hand, when it is determined that the acquired line width is not smaller than the target line width Wm, the control unit 500 skips step S470 and proceeds to step S480.

Thereafter, in step S480, the control unit 500 determines whether the formation of the first layer LY1 is completed. The control unit 500 can determine whether the formation of the first layer LY1 is completed using the shaping data. When it is determined that the formation of the first layer LY1 is not completed, the control unit 500 returns the processing to step S420, and continues the formation of the first layer LY1. When the flow rate is corrected in step S470, in step S430 or step S440, the control unit 500 controls the discharge amount adjusting mechanism 70 to discharge the shaping material at the corrected flow rate. On the other hand, when it is determined that the formation of the first layer LY1 is completed, the control unit 500 ends the first shaping step and starts the second shaping step as shown in FIG. 8.

According to the three-dimensional shaping device 100 c of the present embodiment described above, when the line width of the shaping material linearly deposited on the stage 300 is smaller than the target line width Wm, the control unit 500 corrects the supply amount of the shaping material such that the line width of the shaping material approaches the target line width Wm. Therefore, the case where the line width of the shaping material is narrower than the target line width Wm is reduced.

D. Other Embodiments

(D1) FIG. 19 is a top view showing a configuration of a stage 300 d on the shaping surface 311 side according to another embodiment. According to the three-dimensional shaping devices 100, 100 b, and 100 c of the above embodiments, the recessed portions 315 of the stage 300 are formed by a plurality of through holes provided in the plate portion 310. In contrast, as shown in FIG. 19, a plate portion 310 d of the stage 300 d is not provided with the through holes, and the recessed portions 315 d are formed by grooves in a grid in the plate portion 310 d. A shape of the groove provided in the plate portion 310 d is not limited to the grid, but may be, for example, a concentric circular shape.

FIG. 20 is a diagram showing a cross section of the recessed portion 315 d of the stage 300 d according to another embodiment. FIG. 21 is a graph showing a relationship between a position on the stage 300 d and a supply amount of a shaping material according to another embodiment. In FIG. 21, the horizontal axis represents the position on the stage 300 d, and the vertical axis represents the supply amount of the shaping material supplied on the stage 300 d per unit area. A groove forming the recessed portion 315 d of the stage 300 d may have, for example, an inclined surface 316 inclined with respect to the shaping surface 311 as shown in FIG. 20. According to the embodiment shown in FIG. 20, a distance along a direction perpendicular to the shaping surface 311 from a surface along the shaping surface 311 to the inclined surface 316 increases toward a center of the groove. That is, a depth of the recessed portion 315 d increases toward the center of the groove. In the first shaping step, as shown in FIG. 21, the control unit 500 may increase the first supply amount S1 as the depth of the recessed portion 315 d increases, and may decrease the first supply amount S1 as the depth of the recessed portion 315 d decreases. In this case, even when a part of the shaping material supplied on the stage 300 d enters the recessed portion 315 d having the inclined surface 316, it is possible to reduce the unevenness on the upper surface of the first layer LY1.

(D2) According to the three-dimensional shaping devices 100, 100 b, and 100 c of the above embodiments, the control unit 500 makes the first supply amount S1 larger than the second supply amount S2 by controlling the discharge amount adjusting mechanism 70 to adjust the flow rate of the shaping material discharged from the nozzle hole 69. In contrast, the control unit 500 may make the first supply amount S1 larger than the second supply amount S2 by controlling the discharge amount adjusting mechanism 70 not to adjust the flow rate of the shaping material discharged from the nozzle hole 69, and controlling the moving mechanism 400 to make a relative speed between the nozzle hole 69 and the stage 300 when discharging the shaping material to the first region RG1 slower than a relative speed between the nozzle hole 69 and the stage 300 when discharging the shaping material to the second region RG2. In this case, even when the flow rate of the shaping material discharged from the nozzle hole 69 cannot be increased, the first supply amount S1 can be made larger than the second supply amount S2. Even without the discharge amount adjusting mechanism 70, the supply amount of the shaping material can be adjusted with a simpler configuration. The control unit 500 may make the first supply amount S1 larger than the second supply amount S2 by adjusting both the relative speed between the nozzle hole 69 and the shaping surface 311 and the flow rate of the shaping material discharged from the nozzle hole 69.

(D3) According to the three-dimensional shaping devices 100, 100 b, and 100 c of the above embodiments, the control unit 500 makes the first supply amount S1 larger than the second supply amount S2 by controlling the discharge amount adjusting mechanism 70 to adjust the flow rate of the shaping material discharged from the nozzle hole 69. In contrast, the control unit 500 may make the first supply amount S1 larger than the second supply amount S2 by controlling the drive motor 32 to adjust a rotation speed of the flat screw 40.

(D4) According to the three-dimensional shaping devices 100, 100 b, and 100 c of the above embodiments, when the shaping data is generated, the first region RG1 and the second region RG2 may be set, and the shaping data in which the first supply amount S1 is larger than the second supply amount S2 may be set in advance. In this case, the supply amount of the shaping material supplied from the nozzle hole 69 to the first region RG1 per unit area is set to be the same amount as the supply amount according to the shaping data and the first layer LY1 is formed, and the supply amount of the shaping material supplied from the nozzle hole 69 to the second region RG2 per unit area is set to be the same amount as the supply amount according to the shaping data and the first layer LY1 is formed, so that the first supply amount S1 can be made larger than the second supply amount S2.

(D5) According to the three-dimensional shaping devices 100, 100 b, and 100 c of the above embodiments, the control unit 500 sets, as the first region RG1, a region in which a region on the recessed portion 315 and a region outside an edge of the recessed portion 315 within a distance half the target line width Wm of the shaping material from the edge of the recessed portion 315 are combined. In contrast, the control unit 500 may set the region on the recessed portion 315 as the first region RG1 without including the region outside the edge of the recessed portion 315 within the distance half the target line width Wm of the shaping material from the edge of the recessed portion 315 as the first region RG1.

(D6) According to the three-dimensional shaping devices 100, 100 b, and 100 c of the above embodiments, the melting unit 30 includes the flat screw 40 and the barrel 50, and melts the material using the relative rotation of the flat screw 40 and the barrel 50. In contrast, the melting unit 30 may include, instead of the flat screw 40, an inline screw in which a spiral groove is formed in a long shaft and a cylindrical barrel surrounding the inline screw, and may have a form in which the material is melted using a relative rotation of the inline screw and the cylindrical barrel.

(D7) According to the above embodiments, the three-dimensional shaping devices 100, 100 b, and 100 c that include the flat screw 40 and the barrel 50, and that melt the material using the relative rotation of the flat screw and the barrel 50 are used. In contrast, a fused deposition modeling (FDM) three-dimensional shaping device may be used. In this case, the first supply amount S1 may be made larger than the second supply amount S2 by adjusting a feed speed of a filament used as the material.

E. Other Embodiments

The present disclosure is not limited to the above-described embodiments, and can be implemented in various aspects without departing from the spirit of the present disclosure. For example, the present disclosure can be implemented by the following aspects. In order to solve some or all of the problems described in the present disclosure, or to achieve some or all of the effects of the present disclosure, technical characteristics in the above embodiments corresponding to the technical characteristics in each of the embodiments described below can be appropriately replaced or combined. If the technical characteristics are not described as essential in the present description, they can be deleted as appropriate.

(1) According to a first embodiment of the present disclosure, a method for manufacturing a three-dimensional shaped object is provided. The method for manufacturing a three-dimensional shaped object includes: a first shaping step of forming a first layer in contact with a stage provided with a recessed portion by changing a relative position between a discharge unit and the stage while discharging a molten material from the discharge unit toward the stage; and a second shaping step of stacking one or more layers on the first layer by changing the relative position between the discharge unit and the stage while discharging the molten material from the discharge unit toward the first layer. The stage has a first region including a region on the recessed portion and a second region different from the first region, and in the first shaping step, the first layer is formed by making a first supply amount which is a supply amount of the molten material supplied from the discharge unit to the first region per unit area larger than a second supply amount which is a supply amount of the molten material supplied from the discharge unit to the second region per unit area.

According to the method for manufacturing a three-dimensional shaped object in this embodiment, it is possible to reduce unevenness on an upper surface of the first layer due to a part of the molten material supplied on the stage entering the recessed portion. Therefore, it is possible to improve dimensional accuracy of a three-dimensional shaped object manufactured by stacking molten materials on the stage including the recessed portion.

(2) In the method for manufacturing a three-dimensional shaped object according to the above embodiment, in the first shaping step, the first supply amount may be made larger than the second supply amount by making a first flow rate of the molten material discharged from the discharge unit toward the first region larger than a second flow rate of the molten material discharged from the discharge unit toward the second region.

According to the method for manufacturing a three-dimensional shaped object in this embodiment, the first supply amount can be easily made larger than the second supply amount.

(3) In the method for manufacturing a three-dimensional shaped object according to the above embodiment, in the first shaping step, the first supply amount may be made larger than the second supply amount by making a first relative speed between the discharge unit and the stage when discharging the molten material from the discharge unit toward the first region slower than a second relative speed between the discharge unit and the stage when discharging the molten material from the discharge unit toward the second region.

According to the method for manufacturing a three-dimensional shaped object in this embodiment, even when the flow rate of the molten material discharged from the discharge unit toward the stage cannot be increased, the first supply amount can be made larger than the second supply amount.

(4) The method for manufacturing a three-dimensional shaped object according to the above embodiment may further include acquiring a relative position between the discharge unit and the first region by detecting a position of the recessed portion.

According to the method for manufacturing a three-dimensional shaped object in this embodiment, the position of the first region can be acquired without acquiring in advance the position of the recessed portion.

(5) In the method for manufacturing a three-dimensional shaped object according to the above embodiment, the recessed portion has an inclined surface inclined with respect to an upper surface of the stage, and in the first shaping step, the first supply amount may be adjusted according to a distance from the upper surface of the stage to the inclined surface along a direction perpendicular to the upper surface of the stage.

According to the method for manufacturing a three-dimensional shaped object in this embodiment, even when a part of the molten material supplied on the stage enters the recessed portion having the inclined surface, it is possible to reduce the unevenness on the upper surface of the first layer.

(6) In the method for manufacturing a three-dimensional shaped object according to the above embodiment, in the first shaping step, a line width of the molten material linearly disposed on the stage may be measured, and the first supply amount and the second supply amount may be adjusted using the measured line width.

According to the method for manufacturing a three-dimensional shaped object in this embodiment, it is possible to reduce the case where a line width of the molten material linearly deposited on the stage is narrower than a target.

(7) In the method for manufacturing a three-dimensional shaped object according to the above embodiment, the first region may be a region in which a region on the recessed portion and a region outside an edge of the recessed portion within a distance half the line width of the molten material from the edge of the recessed portion are combined.

According to the method for manufacturing a three-dimensional shaped object in this embodiment, since it is possible to reduce a shortage of the molten material supplied to a region on the recessed portion and an excessive supply of the molten material to a region away from the recessed portion, it is possible to more reliably reduce the unevenness on the upper surface of the first layer.

The present disclosure can be implemented in various forms other than the method for manufacturing a three-dimensional shaped object. For example, the present disclosure can be implemented in forms of a three-dimensional shaping device and a method for controlling the three-dimensional shaping device. 

What is claimed is:
 1. A method for manufacturing a three-dimensional shaped object, comprising: a first shaping step of forming a first layer in contact with a stage provided with a recessed portion by changing a relative position between a discharge unit and the stage while discharging a molten material from the discharge unit toward the stage; and a second shaping step of stacking one or more layers on the first layer by changing the relative position between the discharge unit and the stage while discharging the molten material from the discharge unit toward the first layer, wherein the stage has a first region including a region on the recessed portion and a second region different from the first region, and in the first shaping step, the first layer is formed by making a first supply amount which is a supply amount of the molten material supplied from the discharge unit to the first region per unit area larger than a second supply amount which is a supply amount of the molten material supplied from the discharge unit to the second region per unit area.
 2. The method for manufacturing a three-dimensional shaped object according to claim 1, wherein in the first shaping step, the first supply amount is made larger than the second supply amount by making a first flow rate of the molten material discharged from the discharge unit toward the first region larger than a second flow rate of the molten material discharged from the discharge unit toward the second region.
 3. The method for manufacturing a three-dimensional shaped object according to claim 1, wherein in the first shaping step, the first supply amount is made larger than the second supply amount by making a first relative speed between the discharge unit and the stage when discharging the molten material from the discharge unit toward the first region slower than a second relative speed between the discharge unit and the stage when discharging the molten material from the discharge unit toward the second region.
 4. The method for manufacturing a three-dimensional shaped object according to claim 1, further comprising: acquiring a relative position between the discharge unit and the first region by detecting a position of the recessed portion.
 5. The method for manufacturing a three-dimensional shaped object according to claim 1, wherein the recessed portion has an inclined surface inclined with respect to an upper surface of the stage, and in the first shaping step, the first supply amount is adjusted according to a distance from the upper surface of the stage to the inclined surface along a direction perpendicular to the upper surface of the stage.
 6. The method for manufacturing a three-dimensional shaped object according to claim 1, wherein in the first shaping step, a line width of the molten material linearly disposed on the stage is measured, and the first supply amount and the second supply amount are adjusted using the measured line width.
 7. The method for manufacturing a three-dimensional shaped object according to claim 1, wherein the first region is a region in which a region on the recessed portion and a region outside an edge of the recessed portion within a distance half the line width of the molten material from the edge of the recessed portion are combined.
 8. A three-dimensional shaping device comprising: a discharge unit configured to discharge a molten material toward a stage provided with a recessed portion; a moving mechanism configured to change a relative position between the discharge unit and the stage; and a control unit configured to execute a first shaping control for forming a first layer in contact with the stage by changing the relative position between the discharge unit and the stage while discharging the molten material from the discharge unit toward the stage and a second shaping control for stacking one or more layers on the first layer by changing the relative position between the discharge unit and the stage while discharging the molten material from the discharge unit toward the first layer, wherein the stage has a first region including a region on the recessed portion and a second region different from the first region, and in the first shaping step, the control unit forms the first layer by making a first supply amount which is a supply amount of the molten material supplied from the discharge unit to the first region per unit area larger than a second supply amount which is a supply amount of the molten material supplied from the discharge unit to the second region per unit area. 